This proposal requests funds for a high resolution mass spectrometer, liquid chromatograph, and appropriate interfaces to provide LC/MS capability to four major NIH users. The requested instrumentation is currently unavailable to these users. This equipment will allow expansion of the services currently offered by the UCR-supported mass spectrometry facility without elimination of any service currently provided to users throughout southern California. The instrumentation will be operated under the supervision of the principal investigator as is currently in effect to ensure timely analyses.